


a study on aliens

by itsbabiehours



Category: South Park
Genre: Alien/Human Relationships, Aliens, M/M, Mpreg, Size Difference
Language: English
Status: Completed
Published: 2020-12-22
Updated: 2020-12-22
Packaged: 2021-03-11 02:48:33
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 4,552
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28247919
Author URL: https://archiveofourown.org/users/itsbabiehours/pseuds/itsbabiehours
Summary: Astronaut Kyle Broflovski finally gets his chance to explore an alien planet, and he comes across something that he didn't expect.
Relationships: Kyle Broflovski/Stan Marsh
Comments: 2
Kudos: 40
Collections: South Park Mpreg Discord Secret Santa





	a study on aliens

**Author's Note:**

> wrote this for a secret santa!! the au itself belongs to https://twitter.com/nsj8fw and i highly recommend checking out their art c:  
> enjoy!!

Kyle hadn’t ever expected to become an astronaut.

When Kyle had gotten employed at NASA, he had intended to spend his entire life working as a scientist. Kyle was good at statistics, was good at calculating things. He enjoyed tangible, earthly things, things that he already knew how to process and understand. He definitely wasn’t good at surviving in low-gravity environments, and he definitely wasn’t good at communicating with alien species, which was why it came as such a surprise when he was requested to join a new team of astronauts.

Rumor had it that he had only been selected due to a lack of acceptable applicants, and due to the hundreds of scientific breakthroughs that NASA had been accomplishing. Kyle had never expected to witness the discovery of one new planet in his lifetime, let alone several, but he was only in his early twenties and new planets were already being discovered yearly. 

Whatever the reason for his employment was, Kyle knew that he couldn’t pass up an opportunity like this. Millions of people dreamed of going to space, to seeing the vast universe up close, and Kyle had to admit that he was one of them. He simply hadn’t ever expected it to happen.

His training, in total, took nearly two years. It was rigorous, filled with a lot of nausea during the first few months, but he grew accustomed to a zero gravity environment quicker than he would have thought. Some of the other astronauts on his team didn’t fare as well. 

The planet was large, located in the far reaches of the solar system, and while Kyle didn’t particularly know what to expect, he and the rest of his team had been preemptively alerted that the beings present on the planet did possess some level of human intelligence. On one hand, this was encouraging. Kyle was about to become one of the first people in history to communicate with an alien species, and if these creatures really were as intelligent as the staff back at base seemed to claim, he might even have a chance at understanding them, even if only through gestures. It was surely a mission that would be written about in the history books.

On another hand, if these creatures were as intelligent as they seemed, they would surely realize that the astronauts coming to visit their planet were intruders, and likely would dispose of them as they saw fit. This was not an encouraging idea.

But by now, there was no way to back out. Kyle had been in space for several years, as the planet was a great distance away, and he refused to order the space station to turn back now without placing his feet on solid ground. 

…

“Looks like we’re finally here.” Craig peered out through one of the circular windows of the space station. “Took us long enough.”

Kyle hurried towards the window when he heard Craig’s words, pushing him to the side to glance out through the reinforced plastic, resulting in a scowl from his fellow astronaut. “Jesus, dude.” Kyle breathed, gazing out onto the large planet that the ship was rapidly approaching. The planet was covered with something similar to grass, colored in an off-blue shade, and Kyle wondered how the grass would feel under his feet. It had been so very long since he had been on the surface of a planet, and while he was tempted to sprint out and flop down onto the grass, he didn’t want to risk exposing his skin to something dangerous. 

It took the two of them fifteen minutes to suit up, and Kyle fucked up the process twice, his fingers fumbling with his eagerness to finally meet the aliens he had heard so much about. When he returned to glance out the window again, his breath clouding the shield of his helmet, it quickly became apparent that something had changed about the terrain. The grass-like substance nearest to the ship was smushed down in a pattern vaguely resembling a human footprint, and Kyle swallowed, glancing over at Craig. Craig seemed to have made the connection as well, as his face paled. “So. Ready to be the first human to step foot on this planet?”

“What? Why do I have to go first?” Kyle took a few steps back from the window, wondering just how fucking huge the inhabitants of this planet were.

“Because I said so.” Craig began nudging Kyle towards the exit door of the space ship. “If you end up splattered on the ground, I’ll make sure to tell them to hold a funeral back home.”

“Asshole.” Kyle grumbled. He triple checked his oxygen tank, squished his curls under his helmet, and pressed the button to open the sliding door. He took a long, deep breath, and immediately regretted the waste of oxygen, but still stepped outside the door. Craig gave him an ingenuine thumbs up through the window. Kyle flipped him the bird, and Craig returned the gesture, hitting the button again to shut the door as soon as Kyle was out.

Kyle couldn’t feel the texture of the grass under his padded boots, but the blades weren’t poking through his clothing and impaling him, which he assumed was a good sign. He reached down to pluck a blade of grass out of the ground, and he tucked it in his pack, deciding he could send it back to base for analysis. Fortunately, the creature that had presumably created the footprint didn’t seem to be nearby, and Kyle gazed down at the smushed grass for a long moment before beginning his trek.

Really, he wasn’t quite sure what he was looking for. By now, Craig had likely left the ship to go search for samples, and Kyle wasn’t keen on encountering the huge creature again until he had some backup. He had been informed that the creatures were intelligent, and ‘bigger than the average human’, but they hadn’t told him that they would be this big. The footprint itself was nearly half the size of their spaceship, and while Kyle didn’t exact enough dimensions to make any real calculations, the creature was likely over ten meters tall. Likely even taller. Kyle shoved down the trickle of fear in his stomach, and continued his walk, determined not to return to the ship until he had found something of substance.

Kyle walked for nearly an hour, which was quite an effort with his heavy suit strapped to his body. His legs felt weak and tired by the time he had walked for so long, but he had successfully managed to collect several more samples; a handful of strange purple dirt from under the grass, a small rock that crumbled in his hand if he held it too tightly, and something that appeared to be part of the horn of an animal. A very large animal. 

Rationally, Kyle knew that he should turn around and return to the spaceship. Taking a break during an expedition was never a good idea, as it left him vulnerable, but while the samples he had collected were undeniably useful, they weren’t what he was looking for. The chemical properties of the items he had gathered were certainly strange, but nothing out of the ordinary enough to warrant immediate contact back to base. Kyle wanted to collect something interesting. Purple dirt didn’t count as interesting. It only took another five minutes of walking for Kyle to locate a large, fallen log. The wood seemed slightly rotted, and it bent under his fingers if he pushed down on it, but it was at least stable enough to allow for a few minutes of rest. He dug through his pack for one of the rocks that he had picked up, and began inspecting it, deciding that he could at least do something productive with his time.

Ten minutes passed, and Kyle’s legs were beginning to feel a little bit stronger. He was just about to force himself to his feet when he felt a pull from the back of his suit. “Wh-“ He didn’t have time to react before he was being lifted into the air, and he let out a shout, thrashing to try and escape the unknown force that was lifting him up. “What the fuck? Let me go!” 

Kyle was in such a panic that it took him several seconds to make the connection that whatever was lifting him up had to be one of the aliens inhabiting this planet. No wonder it wasn’t dropping him. It probably couldn’t even understand English. He was about to try and wriggle around to get a glimpse of the figure, but the fingers gripping the back of his spacesuit did it for him, turning him around to inspect him. After a brief moment of hesitance, two of the creature’s large fingers came to grip either side of his helmet, plucking it off of his head. “Hey! Wait! I need that to breathe!” Kyle frantically attempted to grab the helmet back, and just when he was about to suck in a final breath of air, he realized that there was no need to. He took in a tentative inhale, held the air inside of his lungs for several seconds, and breathed out. The air here was breathable. If Kyle was in any other situation, he would have pulled out his notepad to make a note of this, but right now, he was busy trying to make sure the creature holding him up didn’t kill him.

Now that the impending threat of dying by suffocation was over, Kyle was able to blink a few times, taking in the huge creature in front of him. 

The creature was huge, just as Kyle had expected. He couldn’t make a completely accurate measurement, but he was able to estimate, and just from a quick scan over its body, it appeared to be over 15 meters tall. His eyes flickered up to the creature’s face, which was rather humanoid in nature. It had two distinguishable eyes, even if they were far larger than would be proportional, and while the creature appeared to lack a prominent pair of lips, its mouth was still there. It opened its mouth, as if it could tell what Kyle was thinking, revealing a set of fangs and a forked tongue. Atop of its head was shaggy black hair, with two long, almost furry antennae protruding from the locks. Its ears were oddly shaped, and if this creature wasn’t currently walking on land, Kyle would have associated it with some kind of fish-like life form.

Kyle wasn’t sure how these aliens perceived gender, or if they even had multiple different genders, but the creature in front of him appeared to be masculine, if going by human standards. The creature blinked a few times, exposing two horizontal pupils, and before Kyle knew it, he was being lifted up closer to the creature’s mouth by a large hand.

“Hey! Wait!” Kyle cried, thrashing wildly. The creature held him above his mouth for a few seconds, looking as though it was going to drop him onto its forked tongue, but just as the grip around the back of his spacesuit loosened, the creature seemed to hesitate. One of the fingers of the hand holding Kyle reached to pat at his hair.

“Dude, I don’t like random aliens touching my hair-“ Kyle started, but the creature seemed to be delighted by Kyle’s bouncy curls, and if this was going to keep him alive for longer, Kyle wasn’t going to complain. Actually, the finger on his hair would have felt kind of nice, if it weren’t for the fact that he had been about to die just seconds earlier. The creature brought him close, and made a sniffing noise, ruffling some of Kyle’s curls with the force of his breath. 

He held Kyle close to his inhuman nose for another long moment, sniffing him, before seeming to be satisfied with whatever he had been doing. He hung limply between the creature’s fingers, not wanting to risk thrashing and being dropped nearly fifteen meters to the ground. He leaned closer to Kyle, and just when Kyle was about to fear that he would be placed in his mouth again, he licked Kyle’s spacesuit, from the toes of his boots to his hair. “Hey! Stop! That tickles!” Still, Kyle couldn’t stop himself from laughing, maybe just from the insanity of the situation, and the creature made a pleased noise, his mouth curling up into something that looked like a grin.

The creature gave Kyle one more lick from head to toe before bringing him close to his neck. Kyle was just about to ask what he was doing, unable to resist speaking despite knowing the creature didn’t understand him, when he was suddenly dropped. His mouth opened in a scream, but he quickly realized that he wasn’t falling to the ground. He fell just over a meter before landing in something furry. He forced himself to his feet, peeking out of wherever he was, and it immediately became apparent that he was in some kind of pouch. Or pocket. 

The creature noticed that Kyle was peering out of his pouch, and he did that expression that almost looked like a grin again, bringing a hand to pat at his hair. This time, Kyle didn’t mind it as much.

Where was the creature taking him? Part of Kyle suspected that he was being taken to wherever the creature lived, perhaps as a food source, but that seemed unlikely. If the creature wanted to eat him, he could have done so already. But if he wasn’t going to be used for sustenance, what did the creature want with him? 

If this creature’s species interpreted gestures the same way that humans did, then the creature had been smiling. And patting at his hair. Both of which didn’t have any negative connotation to them.

Kyle spent at least fifteen minutes musing over this, and by the time he managed to snap himself out of his thoughts, the creature was still moving. There was no way Kyle could escape even if he wanted to, and he was beginning to realize that he didn’t yet want to escape the creature’s gasp. His curiosity was nearly overwhelming. Did this creature have a name? How did he compare to the rest of his species? Where was he taking Kyle? 

Kyle knew that he wasn’t going to be getting answers to any of these questions until the creature took him where he intended to, and Kyle suspected that it was going to be quite a long journey, which was fine with Kyle. He was used to long journeys by now. He carefully slumped back down into the creature’s pouch, deciding that whatever happened next, he would need his energy to deal with it. He leaned back against the creature’s fur, the softness surprisingly comforting, and the last thing he felt before he dozed off to sleep was a large finger combing through his curls.

…

The place where the creature took Kyle wasn’t a ‘house’, in the traditional sense of the word, and Kyle felt somewhat foolish for having expected something like that. Of course this creature wouldn’t live somewhere confined. It would crash through the roof within seconds.

Instead of being brought to an indoor space, the creature brought Kyle to a wooded area. He scooped him out of the small pocket on his neck, held him in one of his hands, and carefully placed him down on the soft, blue grass. From there, the creature flopped down into a sitting position, and for a few seconds, Kyle was afraid that the movement was going to cause an earthquake.

Kyle gazed up at the creature’s large face for a moment, before attempting to speak once more. “What’s your name?”

Unsurprisingly, the creature didn’t respond. It cocked its head, like some kind of confused puppy. Kyle decided that he would have to approach this from another angle.

Kyle pointed to himself, speaking loudly, hoping that the creature’s ears were strong enough to pick up his voice from far away. “Kyle.” He said. “Kyle. That’s my name.” he pointed back at Stan. “What’s yours?”

The creature clearly wasn’t stupid, and now that it had some kind of understanding of what Kyle was trying to convey, he immediately brightened up, seeming excited to have some kind of communication with him. The creature made a throaty noise, while the word that left its mouth didn’t line up exactly with any name on Kyle’s planet, the closest match was ‘Stan’.

“Stan.” Kyle repeated. The creature, Stan, seemed delighted by this, and he reached to scoop Kyle back up into one of his hands, bringing him to his face. He nuzzled his nose against Kyle’s smaller body, and Kyle laughed, gently patting at Stan’s cheek. “Okay, thank you. That’s enough.”

Stan hesitated for just a few seconds before pressing his lips almost tenderly to Kyle’s head. It was a pathetic excuse for a kiss, assuming that was Stan’s intention, but Kyle still found it sweet in a strange way. He could hear Stan’s chest rumbling, almost as if he was purring, and Kyle felt a spark of affection between his ribs. “You’re pretty sweet for a sixty foot tall alien monster.” He murmured, mostly just talking to himself at this point, but Stan seemed to at least understand the tone in his words, because he ‘kissed’ him once more before placing him down in his lap. 

…

From there, things progressed rather quickly. At first, Kyle had managed to convince himself that he was doing this in the pursuit of science.

Letting Stan gather food for him and feed him was just in the pursuit of science. How else would people from Earth find out what food from this planet tasted like? Letting Stan carefully strip him of his clothes and bathe him was also in the pursuit of science. He just wanted to find out what this planet’s water felt on his skin.

Stan was continuously sweet, despite the language barrier between the two of them. He did his best to communicate to Kyle through words, and when he couldn’t, he conveyed his emotions through gestures. He had a possessive streak, to the point where he always placed Kyle in his neck pocket and hid him whenever he passed another alien on the planet, but Kyle didn’t mind. Craig was somewhere out there exploring the planet. He could worry about meeting the other aliens. In the meantime, Kyle was just enjoying this.

While Kyle might have been able to convince himself that sitting on an alien’s lap and sharing food with him was just in the pursuit of science, he stopped being able to use that excuse by the time he was sitting on said alien’s nude lap.

Needless to say, sex with an alien twenty times your size wasn’t easy. It was awkward at first, as both of them wordlessly attempted to figure out what they needed to do, but they eventually got there. Stan clearly couldn’t fit inside of Kyle, so he simply placed the human on the tip of his cock. Kyle grinded down against him, and Stan stroked himself all the while, keeping one of his hands in front of Kyle to catch him if he happened to fall.

Honestly, it was more pleasurable than Kyle had expected. He slumped forward once he had finished, his entire body feeling melty and weak, and Stan immediately scooped him up, cooing affectionately into his ear.

…

“Dude, come on, let me go-“ Kyle attempted to wriggle out of Stan’s neck pocket, but Stan quickly reached for him, cradling him in his hands and cooing soothingly at him. Kyle sighed, relaxing reluctantly back into the hands around him. For the past few weeks, Stan had become increasingly overprotective to the point where he refused to let Kyle even walk around, fretting about him potentially getting squished whenever Kyle complained.

Kyle appreciated the alien’s care, but it was quickly becoming aggravating. He could take care of himself. He was an astronaut, had trained for these kind of situations, and he didn’t need an alien to protect him from any danger whatsoever. “Come on. I’m fine. Just let me go.” He swatted at one of Stan’s fingers, which simply got him a pat on the head in return.

Kyle groaned. “Why have you been like this lately? Jesus fuck. Nothing’s changed. I’m going to have forgotten how to walk by the time you put me down again.”

Stan still struggled with breaching the language barrier between the two of them, but he had learned a few key words, and it had significantly enhanced their communication. He hesitated for a second, unsure as to whether this was the right word, before reaching to gently poke Kyle’s stomach. “Baby.”

“Baby?” Kyle glanced down at his stomach, before glancing back up at Stan. “What do you mean by ‘baby’?”

“Baby.” Stan repeated, gently brushing his thumb over Kyle’s abdomen. “My baby.”

“Your…” Kyle’s eyes widened. “You don’t mean…?”

Stan nodded, seeming delighted by Kyle’s understanding. “Our baby.”

Kyle stared down at his stomach for another long moment, carefully bringing his hands down to touch his abdomen. Suddenly, the events of the past few weeks made sense. Kyle had been strangely sick for most of the time, the sickness starting about a week after he and Stan had slept together, and while he hadn’t even thought about associating it with morning sickness, that suddenly felt like the only explanation that fit.

Kyle was a biological male. Back on Earth, there was no way he could ever get pregnant. Was something different here? Did alien seed have some special properties? Either way, Stan seemed absolutely convinced that Kyle was pregnant, and seeing as his symptoms matched up, he definitely wasn’t going to argue.

Was Kyle even ready to have a baby? Was he even ready to have a baby with an alien as the father? He supposed that it was too late now to ask himself those questions. And if Stan was this good at taking care of him, he knew that he would be just as good about taking care of their baby. Their baby. It still didn’t seem real.

“I guess you can keep taking care of me, then.” Kyle agreed reluctantly. He still didn’t want to spend the next eight months in Stan’s neck pouch, being constantly fretted over, but he could at least understand the alien’s motivations a little bit more now. 

Stan beamed, and he brought Kyle close to his lips to plant a gentle kiss on his forehead before gently sliding him back into the pocket.

…

“Dude, I’m full.” Kyle groaned, attempting to push one of Stan’s far larger hands away from him. “Just let me sleep.”

Stan cocked his head to the side, attempting to press another piece of unfamiliar cooked meat into Kyle’s hands. Kyle didn’t know exactly how long it had been, as time seemed to pass differently on this planet than it did on Earth, but his baby bump had now become a prominent feature on his body. During that time, he had gained at least fifteen pounds. Stan was very insistent on making sure that he was well fed, and ‘well fed’ seemed to mean a different thing to aliens than it did to humans.

Stan gave him his best puppy dog eyes, and Kyle let out a sigh, reluctantly reaching to take the slice of meat from the alien. “Fine. But just one more. Then I’m not eating again until tomorrow.” He stated firmly, forcing himself to finish up the small piece of meat. Stan lifted him towards his face to nuzzle his nose against him, seeming very grateful.

“I know, I know. But I promise the baby’s going to be healthy. You don’t need to stuff me.” Kyle insisted, carefully resting his hands on his large baby bump. At first, Kyle had been fearful; Stan was so much larger than him, and Kyle had been worried that the baby would grow quickly enough to tear him apart by month 2. Fortunately, that didn’t seem to be the case.

Kyle had no idea whether these aliens had ever reproduced with humans before, but Stan hadn’t seemed concerned at all about Kyle’s fears. The baby was certainly growing quicker than usual, as Kyle was barely halfway through his pregnancy but still looked like he was in month 8, but it wasn’t growing quickly enough to explode Kyle from the inside out. It was a big baby, but not big enough to kill him, and that was all that mattered to Kyle. 

Stan reached to gently poke at Kyle’s baby bump, and he squirmed, trying not to smile at the alien’s affectionate gesture. “Mhm. We’ll get to see it soon.” He reassured, tilting his head to press a kiss to Stan’s much larger nose. The alien crinkled his nose, clearly not having been expecting that. He seemed almost confused about the intentions of the gesture, but quickly realized that it was affectionate, and returned it with a kiss of his own, lifting Kyle up to press their foreheads together.

…

Birth was an unsurprisingly unpleasant ordeal.

Kyle’s chest heaved with heavy breaths, his eyes shut tightly as sweat rolled down his forehead. Stan appeared to be panicking, caught between wanting to scoop Kyle up and cradle him and not wanting to see him in pain. 

It took nearly nine hours for the baby to be born, and by the time he finally heard the cry of his child, he was just about ready to pass out from exhaustion. The cry barely even registered with him; the thing that alerted him to the birth of his child was the tears suddenly welling up in Stan’s eyes. “Baby.” The alien whispered. Kyle had heard Stan say that word hundreds of times over the past few months, but it still never got old. He was too weak to sit up just yet, so Stan scooped the baby up with two of his large fingers, and carefully placed it on Kyle’s chest.

It was larger than a human baby, but not completely out of the average size range of one. Kyle almost would have been able to mistake it for a human, if it weren’t for the fluffy ears poking out of each side of its head, and the two antennae protruding from its curly black hair.

Kyle felt tears begin to swim in his eyes, and he blinked a few times to ward them away, clutching the baby close. He glanced up at Stan, but when he opened his mouth to speak, no words came out. Still, Stan seemed to understand, like he always did, and he gently lifted Kyle up in both of his hands, careful not to shift his positioning too much.

Stan gently poked Kyle’s chest with one of his fingers, causing the baby to squirm, before retracting his finger. He then proceeded to poke his own chest, right where his heart was, and Kyle nodded slowly, his face softening into an expression of pure affection. “Yeah. I love you too, dude.” He breathed, feeling completely and utterly content.


End file.
